The super trio: Olive oil, nuts and avocado

Stanford University School of Medicine researchers believe the fat helps to protect cells from signs of ageing. Photo / 123RF

The magic potion for a long and healthy life could be in your cupboard - in the form of olive oil.

A form of fat found in the staple kitchen ingredient may help people to reach 100 years old, scientists claim.

But be warned - it could also make you put on weight, according to the latest trial of mono-unsaturated fats on worms.

Animals given the healthy compound, which is also found in avocado and nuts, were found to live longer.

This was despite it making them obese - an established indicator of an early death that raises the risk of heart disease and diabetes.

Experts believe the findings may also be relevant to humans as we apparently share similar qualities with the animals.

Stanford University School of Medicine researchers believe the fat helps to protect cells from the signs of ageing.

They also said it allows the body to quickly access energy from foods in the study published in the journal Nature.

Lead author Professor Anne Brunet said: 'We have known for some time metabolic changes can affect lifespan, but we expected the long-lived animals in our study would be thinner.

"Instead, they turned out to be fatter. This was quite a surprise."

It may also explain why southern Europeans, who frequently eat olive oil in their Mediterranean diet, live longer and have lower rates of heart disease, despite consuming more fat.

In the study, roundworms were fed mono-unsaturated fatty acids, which are already known to reduce the risk of heart disease and diabetes.

Not only did the roundworms become obese, but they also lived two days longer on average than their svelte counterparts. Their average lifespan is a fortnight.

Research has previously shown roundworms that lack a complex of proteins called COMPASS live for 30 per cent longer than their peers.

Tests later found blocking COMPASS helped convert unhealthy polyunsaturated fats in the animals' guts into mono-unsaturated fats.

This came as a surprise as severe calorie restriction has also been shown to extend the lifespan of worms and many other animals.

The researchers are now working to understand how the mono-unsaturated fatty acid accumulation might work to extend lifespan.

Humans with diets rich in mono-unsaturated fats have been shown to have a reduced risk for heart disease and diabetes.

Some studies have even shown that centenarians store more mono-unsaturated fat than non-centenarians.

Commenting on the study, London-based nutritionist Rob Hobson said "it has many health benefits" mainly supporting the heart.

Healthspan's head of nutrition added: "It contains unique anti oxidants that reduce inflammation such as oleocanthal.

"Like all healthy foods it's energy dense so by that although good for you you still need to eat in moderation."